SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84272a16efbbb6374f0a290f71e6710345427734846b56cab731ca0092d20ac4' 
  AND token = 'qu7FdHZggj90wBQ/DgUFmBjqeDTzrO5uYHhJZFmdYNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}